1. Field of the Invention
The present invention relates to address detection and/or correction, and more particularly, to a method of and apparatus for efficiently detecting and/or correcting address information in an optical recording and/or reproducing apparatus.
2. Description of the Related Art
In an optical recording and/or reproducing apparatus, an address is important information indicating a location on which information is recorded or is to be recorded. Addresses can be broken down into physical addresses that exist even before user data are recorded on a recording medium, and logical addresses that are recorded together with user data when user data are recorded. In addition to address information, additional information may be recorded together on an area where an address is recorded and at this time, an error correction parity for accurately detecting address information/additional information is recorded together.
FIG. 1 is a block diagram of a conventional optical recording and/or reproducing apparatus.
Referring to FIG. 1, reference number 10 indicates a disc, and the optical recording and/or reproducing apparatus comprises a pickup 11, an automatic laser power control (ALPC) circuit 12, a radio frequency amplifier (RF-AMP) 13, a data processor 14, a host interface (I/F) 15, a host 16, a servo processor 17, a motor and driver 18, a micom 19, and an address detector 141 in the data processor 14.
The ALPC 12 controls the quantity of light of the pickup 11 so as to write data on the disc 10 and the RF-AMP 13 amplifies a minute signal picked up by the pickup 11 from the disc 10. The data processor 14 generates data from the amplified signal, detects a physical address from the generated data, performs writing control for the physical address and logical address, and other operations including synchronization signal detection, insertion, protection, modulation and demodulation, and generates a variety of control signals for the RF-AMP 13 and error correction. In addition, the data processor 14 includes the address detector 141 which detects address and/or additional information of an address area from the generated data, and if there is an error in the detected address and/or additional information, corrects the error, and returns the obtained result whenever address information is needed in the data processor 14.
The host interface 15 interfaces the data processor 14 with the host 16. The servo processor 17 performs servo control, including control of a variety motors related to the disc 10, tracking, and focusing. The motor and driver 18 performs functions for driving motors related to rotation of the disc 10, and the micom 19 controls the operation of the entire system of the optical recording and/or reproducing apparatus.
FIG. 2 is an example of the format of an address area on an optical recording medium.
Referring to FIG. 2, the address area comprises address information, additional information and parity information. Here, in some cases, additional information is recorded based on a specified characteristic with respect to an area of a medium, and in order to find this area, address information should be known. That is, only after address information is known, additional information can be known, and in order to find address information, error correction including additional information should be performed. This lowers the error correction efficiency to the extent that the additional information is needed.
FIG. 3 is a flowchart of operations performed in a conventional method for detecting and/or correcting address information, and will now be briefly explained referring to FIG. 1.
Referring to FIG. 3, when the data processor 14 wants to use address information of a disc or additional information in an address area, the data processor 14 detects a synchronization pattern and data corresponding to the address area in operation 31. Through the detected synchronization pattern, data corresponding to the location of the address area are collected to form the address area data, and then by using the detected value of additional information of the address area without change, an error is detected and/or corrected in operation 32. It is determined whether or not there is an error in the address area data of the operation 32, in operation 33, and if there is no error, the detected address and additional information are used without change in operation 34.
If there is an error in the address area data in the operation 33, it is determined whether or not the error is corrected in operation 35, and if the error is corrected, the error-corrected address and additional information are used in operation 36, and if the error is not corrected, the error is indicated in operation 37.
In an additional information field in an address area, data having a different characteristic depending on an area of a disc is contained. In the related art, however, error correction is performed without considering this characteristic. In particular, even when an additional information field is filled with an already known value, error correction is performed without considering this value. This is because in order to know the value of additional information, a current area should be known. That is, information on the current area is address information, which can be known only after error correction for the address information is performed. In addition, since error correction for address information needs to include the additional information, even though a predetermined value is used as additional information, the value cannot be used unless error correction is performed. Accordingly, in the related art, even though additional information corresponding to a predetermined area of a disc is an already known value, the value cannot be used and this is inefficient in the aspect of error correction.